Let the Brewing Begin! Most recipes say do not start your boil with less than 2.5 gallons, but the more you start with the less you have to add later... Check out the Water topic in Ingredients to understand the types of water options that you should know about. This is also the step that you will start making your wort if you have Specialty Grains! While Steeping your specialty grains keep a close eye on the Temperature!